Abstract

To promote chromosome bi-orientation, Aurora B kinase weakens and disrupts aberrant kinetochore-MT interaction. It has long been debated how Aurora B halts this action when bi-orientation is established and tension is applied across sister kinetochores. Pertinent to this debate, it was shown that Bir1 (yeast Survivin), which recruits Ipl1-Sli15 (yeast Aurora B-INCENP) to centromeres, is dispensable for bi-orientation, raising the possibility that Aurora B localization at centromeres is not required for bi-orientation. Here, we show that the COMA inner kinetochore sub-complex physically interacts with Sli15, recruits Ipl1-Sli15 to the inner kinetochore and promotes chromosome bi-orientation, independently of Bir1, in budding yeast. Moreover, using an engineered recruitment of Ipl1-Sli15 to the inner kinetochore when both Bir1 and COMA are defective, we show that localization of Ipl1-Sli15 at centromeres/inner kinetochores is essential for bi-orientation, refuting the above possibility. Our results give important insight into how Aurora B disrupts kinetochore-MT interaction in a tension-dependent manner, to promote chromosome bi-orientation.

Footnotes

We heard that some people could not properly open Figures of the first version of our pre-print. This may be related to use of Safari and OS-Mojave. In any case, we have re-assembled the PDF using a different method. If anyone still has a problem in opening Figures of this new version, please make comments and let us know.

Copyright

The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC 4.0 International license.